Households and offices generally include a variety of appliances for performing a variety of functions. For example, a household may include a refrigerator appliance, a dishwasher appliance, a microwave appliance, an oven appliance, a washer appliance and/or a dryer appliance. Such appliances typically include user interfaces which allow a user to interact with the appliance and provide commands for operation of the appliance.
One type of user interface is a touch surface user interface, such as a touchscreen or a plurality of touch buttons, wherein the user touches various locations on a plate which is typically formed of plastic or glass. A signal is transmitted to a controller of the appliance, and the controller interprets this signal and controls operation of the appliance based on the signal. The type of signal transmitted to the controller is based on the location on the plate at which the user contacts the plate.
One example of touch surface technology is capacitive touch technology, which generally measures changes in capacitance due to contact by a user with the touch plate. The location of the change in capacitance is sent to a controller for processing. In some cases, self-capacitance technology is utilized. A grid of electrodes is formed on a control board which is connected to the touch surface. To detect capacitance changes, each column and row is independently measured when a touch is occurring. However, such technology has limitations. In particular, when more than one touch occurs simultaneously, such technology is unable to accurately determine these multiple locations, rather indicating “ghost” locations along with correct locations.
More recently, mutual capacitance technology has been utilized. While producing weaker signals than self-capacitance approaches, mutual capacitance technology provides improved location determination accuracy and eliminates “ghosting”. A grid of electrodes is again utilized, but each row (or column) is pulsed in turn and the columns (or rows) are measured for capacitance changes. Accordingly each node (i.e. each intersection between a column electrode and row electrode) is individually measured.
One drawback of presently known mutual capacitance technology is that the control board is typically required to be directly in contact with the touch plate. Accordingly, mutual capacitance applications have been limited to such applications and generally are not utilized when spacing between the control board and touch plate is desired. Recently, U.S. Pat. No. 8,823,675, issued on Sep. 2, 2014 and which is incorporated by reference herein in its entirety, provided disclosure related to the use of springs between the control board and touch plate. However, the springs are either only utilized for the column electrodes or row electrodes (and not both), or are utilized for both column and row electrodes but are spaced apart from each other, thus limiting the capacitance change detection abilities of the subject assemblies.
Accordingly, improved user interface assemblies are desired in the art. In particular, user interface assemblies which include features for facilitating improved mutual capacitance touch technology would be advantageous.